"Do you want my number? It's inside this list:"

You might find it interesting to learn a bit about information theory. The entire purpose of your specific number is precisely to identify which number in that list is yours. Having the list of all possible numbers is irrelevant. Conceptually you can model that as everyone has that, all the time. But that's not enough to do anything with, because having that list entire list means you have zero information.

If you say "it starts with an 8", you've eliminated 90% of the possibilities. Now you have log2(10) bits of information, but you haven't nailed it down yet. For each additional number you give you give that many more bits until you nail it down.

This is a common misconception people have. I remember someone who claimed to have copyright all possible melodies by virtue of having printed them out and thus enumerated them. But that is meaningless, because the entire job of naming a specific melody is precisely the nailing down of which one you mean. Expanding the list of possibilities you might mean is actually a reduction in the amount of information, despite the superficial appearance of listing more numbers out, and when you expand the possibilities out to "all possible instances of the thing" you're actually at the minimum of information, not the maximum.